Doughnuts appear in a number of mathematically classifiable forms, predominantly oblate spheroids and ellipsoids, cylinders with domed ends, and toroids.
The logical progression is to label them not as "ring" or "filled" but by the set of equations that describes their form.
This would be immensely satisfying to mathematicians, physicists, engineers and geeks of all sorts, as questions such as "Do I get more sugar dusting on a small torus or a larger spheroid ?" can be unambiguously resolved before approaching the counter.-- 8th of 7, Apr 01 2014 Not really relevant http://picasaweb.go...vtA?feat=directlinkSpotted in a local bakery window, I think I posted this image before [pocmloc, Apr 02 2014] The sugar-dusting answer is obvious. You need a Sierpinski donut fractal with infinite surface area but zero volume. Infinite amount of sugar dusting but zero calories.-- RayfordSteele, Apr 01 2014 I think that donut should be alternately spelled "doughnut", but this idea renders that spelling reform redundant.
Phew! Just think how many arguments your idea has prevented. Almost enough to warrant a Nobel Peace Prize.
[+] for helping to force those whose maths (which one should quite often call "math") fell somewhere short of topology to resume their quest.-- skoomphemph, Apr 01 2014 I do nut get it.-- pashute, Apr 01 2014 random, halfbakery